The first Diamondback was a foe of Luke Cage. Willis Stryker, one of Luke's childhood friends, first appeared in Luke Cage: Hero for Hire #1. Known as Diamondback for his mastery of knives, including specially-gimmicked knives that exploded, released toxic gases or created sonic waves, he was apparently killed in an explosion in Luke Cage: Hero For Hire #2 (June 1972).

Rachel Leighton was born in Austin, Texas. She was once a part-time sales clerk at a boutique, but later became a mercenary. In Captain America vol. 1 #319 she reveals to Captain America that she has a brother and that when she was younger was introduced by him to the super-criminal known as The Trapster. In exchange for weaponry that The Trapster provides her with, Leighton suggests that in return she prostitutes herself to the criminal. One of the members of the original Serpent Society,[1] Diamondback was a seductively sly woman with expertise in hand-to-hand combat, being trained by Anaconda at Taskmaster's academy. Her gimmick was that she threw acid-laced or poison-tipped diamonds at her enemies. After her first confrontation with Captain America while on assignment to find MODOK,[2] she was instantly smitten. Diamondback was assigned to take Captain America into custody from the Porcupine, but was reluctant to attack him, concentrating her efforts on Porcupine instead.[3] She later attempted a partnership with Captain America to locate the Scourge of the Underworld.[4]

Viper staged a coup of the Serpent Society, causing several of her underlings to infiltrate as new members and setting Viper up to take over by force. Diamondback and their current leader, Sidewinder, escaped, recruiting Captain America and his allies to rescue the Serpents who were still loyal to Sidewinder.[5] After a fierce battle, in which Viper was defeated, Sidewinder abandoned the Serpent Society. Diamondback stayed on for a while under the new leader, Cobra.

Rachel was later revealed to have resigned from the Serpent Society, and somehow temporarily switched bodies with the X-Man, Dazzler. This led, in part, to a confrontation between the Serpent Society and the X-Men.[6] Diamondback later alerted Captain America to the Bloodstone Hunt.[7] She aided Captain America in combat with Batroc, Machete, Zaran, and Baron Zemo.[8] She also encountered Crossbones for the first time.[9] Diamondback later accompanied Captain America to the Red Skull's Skullhouse.[10]

Diamondback and Captain America eventually went on their first date, aided by Rachel's friends in the Serpent Society, Asp, Black Mamba, and Anaconda.[11] She then battled the Black Widow, and acquired a new costume.[12] Diamondback was eventually put on trial by the Serpent Society for her consorting with the enemy (most of the Society assuming, incorrectly, that Diamondback had betrayed their secrets to Captain America) and found guilty for her actions, and almost executed.[13] She escaped with Captain America and Paladin's help, and later hired Paladin to help get revenge on the Serpent Society.[14] Along with her best friends Black Mamba and Asp, she formed "BAD Girls, Inc."[15] After a failed kidnapping attempt from Anaconda, Diamondback was taken aboard Superia's ship, and joined her Femizons under duress.[volume & issue needed] While aboard Superia's ship, she was attacked by the Femizon Snapdragon, of whom Diamondback developed a phobia.[volume & issue needed] After being rescued and then being used as a test subject by the Red Skull to see if the blood packets that Crossbones brought was really Captain America's blood, the super-soldier serum enhanced Diamondback tracked down and confronted Snapdragon, who died in the fight.[volume & issue needed]

Later, there was a glitch discovered in the super-soldier serum that Cap was suffering from and Diamondback went to Superia in hopes for a cure. Using her as a test subject, there was a 50/50 chance that the cure would either work or kill Diamondback. As an added stipulation, if the test was successful, Diamondback had to serve Superia as the second Snapdragon. The experiment was a success, but she later got out of this deal when Superia was killed.[volume & issue needed]

BAD Girls disbanded after that. Some time later, Diamondback was infected with "mind-control nanoprobes" by Baron Zemo. Diamondback suffered extensive neurological damage from the experience and spent an extended period of time recovering in S.H.I.E.L.D. care.[volume & issue needed]

Rachel's brother Danny is also known as Cutthroat. It was Danny and another of her brothers, Ricky, who originally fell in with a gang led by a man known as "Bing." Yearning to be included, she approached Bing alone. Upon claiming she would do anything to join the gang, Rachel was beaten and possibly raped by Bing, who years later became Crossbones, kidnapped her, starved her, and abused her until she agreed, with ulterior motive, to steal packages of Captain America's blood from Avengers Mansion. Bing/Crossbones murdered Danny/Cutthroat, who was attempting to replace him as aid to the Red Skull, and also killed Rachel's third brother, Willy, when, despite being crippled in the military, he sought revenge by rifle for the brutality inflicted on his sister soon after she was originally mistreated.[volume & issue needed]

Diamondback later turned up along with Asp and Black Mamba during the Civil War as a member of the Secret Avengers.[17] She took part in the final battle of the "war", but did not accept the offer of amnesty that came with Captain America's surrender. Later Diamondback and the other BAD Girls were captured by the Mighty Avengers in a New York City street mall.

When Norman Osborn assumes control of the Initiative, Diamondback agrees to work for him.[19] Diamondback is revealed as a member of the Initiative's new team for the state of Delaware, the Women Warriors.[20] After the Constrictor saves her life from a crashing plane, the two begin a sexual relationship.[21] However, Constrictor discovers that she is secretly working for Gauntlet's "Avengers Resistance".[22] Constrictor decides not to say anything but worries about what would happen if she were found out. Both Diamondback and Constrictor are part of the invasion of Asgard. Diamondback tries to contact the Resistance but cannot get through. She debates whether or not to help Thor when Osborn and several others gang up on him. When Maria Hill comes to Thor's defense by firing a rocket launcher at Osborn and his men, Diamondback adds to the explosion by dropping some explosive diamonds. Constrictor saves her and the two argue about her reckless behavior. They witness Sentry killing Ares and Diamondback sees Steve Rogers entering the battlefield.[23] As the Avengers begin to turn the tide in the battle, Diamondback tries to get Steve Rogers' attention and make sure he knows she and Constrictor are on his side. Constrictor misinterprets her actions and think she's abandoning him. She turns to find him but at the same time Sentry attacks Asgard's foundations on Osborn's orders. As Rachel and Constrictor reach out to each other, Asgard falls to the ground.[24] Rachel is dug out by Steve Rogers. Constrictor sees this and thinking Rachel does not love him, flees the scene with Taskmaster. After Osborn's defeat, Rachel attends a party at Avengers Tower where Steve Rogers asks her to coordinate the remaining Fifty State teams. She tells him she'll think about it.[25]

Later, Rachel is shown working as an agent of S.H.I.E.L.D. and sporting a new costume.[26]

A third Diamondback appeared in the Secret War storyline. This Diamondback was Deborah "Debbie" Bertrand. Debbie attended the University of North Carolina on an athletics scholarship, becoming an All-American Olympic athlete and gymnast. For undisclosed reasons, apparently quitting this career to try her hand as a mercenary, she purchased equipment from the Tinkerer, which he had designed for Diamondback (Rachel Leighton). Perhaps hoping to use Leighton's reputation to boost her own fledgling career, Bertrand adopted the same code name, despite Leighton still being active in that identity. Nick Fury thought to himself that when Rachel found out, she would "kick the impostor's butt".[27] Bertrand teamed with Scorcher to attack Daredevil in his apartment. They didn't count on Spider-Man being there and had to retreat. She took part in the battle at Mount Sinai Hospital and was apprehended after the heroes won the day.[28]

A fourth Diamondback, apparently the real Rachel Leighton, resurfaced as a S.H.I.E.L.D. operative, trying to rekindle her romance with Captain America, while in fact she was working undercover for the Red Skull.[29] Truly loving Steve Rogers, but still willing to follow the plot, she was confronted and killed by the Red Skull himself only to "resurrect" herself with a biomechanical form able to take over pieces of technology, like the empowering armor worn by the Nazi villain. Nick Fury then explained that the "new" Rachel was an advanced Life Model Decoy, in fact so advanced as to believe itself to be human, and kept her in storage while working at a way to restore her proper programming. Before "she" could be restored, the Iron Maniac wiped out all her memories, and reshaped her body in a new neurokinetical armor for himself.[volume & issue needed]

Leighton is an athletic woman with no superhuman powers. She has skill in gymnastics, and at pitching small ballistic objects with great accuracy, and at piloting small aircraft. She also has knowledge of general street-fighting techniques, and some jujitsu. Leighton wears a costume of synthetic stretch fabric backed by Kevlar weave, with two biceps-belts and two thigh-belts for carrying throwing diamonds, concealed pockets in the boot tops, boot-heels, glove tops, and brassiere for other throwing diamonds, and throwing diamond earrings. Her personal weaponry consists of throwing diamonds, which are actually 4-inch (100 mm) hollow zirconium octahedrons (though not made of diamond, they are shaped like diamonds) containing various substances; spent uranium, plastic explosives, nitric acid, tear gas, smoke, curare-derived narcotics, etc. Her equipment was originally designed and manufactured by the Trapster, but her later design and manufacture was by the Tinkerer.

The Rachel Leighton version of Diamondback appears as a boss character in Marvel: Ultimate Alliance 2 voiced by Jameela McMillan.[33] She partakes in Lucia von Bardas' attack upon New York. She later is taken over by the mind-control nanites and attacks the heroes alongside Whirlwind and Moonstone at the portal that leads out of the Negative Zone prison.